A tight fit is good. The carrier should come out hard and go in the same way. This is an indicator of correct carrier bearing preload. Interference fit will make you have to use prybars to get the carrier out and a soft-faced, dead-blow hammer to drive it in, complete with shims, making sure you keep it square all the way until seated in the bearing saddles. There are special shim drivers available, but otherwise take great care driving the shims themselves, especially the OE ones. They are very brittle and will shatter.